The present invention relates generally to data storage systems, and, more particularly, to a direct access storage device and formatting method for storing multimedia information.
Advancements in communications technology and increased consumer sophistication have challenged the distributors of multimedia programming to provide the subscribing public with entertainment services more convenient and accessible than those traditionally made available over cable television and telephone systems. An improving communications infrastructure has resulted in a proliferation of pay-per-view media services in many of the larger broadcast markets. Most pay-per-view systems permit the consumer to choose from a relatively small number of motion picture selections for home viewing, with the selected programs generally being presented only at pre-scheduled viewing times.
A number of on-demand video services have been developed that permit the consumer to order desired programs for home viewing through the household telephone line. For example, U.S. Pat. No. 5,247,347, assigned to Bell Atlantic Network Services, discloses a sophisticated video-on-demand telephone service that provides consumer ordered video programming to a plurality of households through use of a public switched telephone network (PSTN). An extensive discussion regarding the inherent deficiencies of communicating video and other multimedia signals over standard bandwidth limited analog telephone lines is provided in the ""347 patent.
The video-on-demand system disclosed in the ""347 patent and other conventional telephony-based multimedia services fail to satisfactorily address the adverse impact to home communications during periods of prolonged program viewing. For example, a typical theatrical motion picture can tie up the household telephone line for over two hours. Further, such sophisticated telephony-based multimedia services generally require procurement of expensive communications and diagnostic equipment by the pay-per-view provider to ensure a reasonable level of signal quality and system reliability. These and other related operating expenses, however, are typically passed on to the consumer.
Importantly, conventional multimedia services fail to provide media presentation control features now expected by the sophisticated consumer after enjoying more than a decade of home entertainment through the use of a video cassette recorder (VCR). Functions such as fast forward, reverse, and pause, for example, are standard presentation control functions now provided by all or most home VCRs, and are typically effectuated by use of an infrared (IR) remote control handset. The limited transmission bandwidth of household telephone lines, as well as common cable television channels, generally precludes accommodation of full VCR-type control functionality when employed to support a conventional multimedia communication system adapted to provide on-demand service to a large number of subscribing customers.
In FIG. 1, for example, there is illustrated a generalized block diagram of a conventional pay-per-view communication service for providing video program distribution to a plurality of households over a public switched telephone network. Movies are typically stored on one or more media servers 10, each of which is multiplexed to the PSTN 16. A telephonic ordering system 14 is generally coupled to the PSTN 16, and provides a means for accepting a pay-per-view order from a customer or user 20 over the telephone. Upon verifying the account status of a user 20, the media server 10 typically transmits the ordered movie or program to a decoder box 22 coupled to the customer""s telephone line 18. The transmitted program is continuously decoded by the decoder box 22 to provide continuous presentation of the selected program on the customer""s television 24. Limitations in the transmission bandwidth of the telephone lines 18, as well as limitations in the switching capability of the PSTN 16, generally preclude the use of a PSTN 16 to support a media communication system that provides high quality, full-motion video signal transmission with full VCR-type control functionality. Such limitations similarly impact a conventional pay-per-view video communication service that utilizes cable television lines.
Other video communication systems, such as that disclosed in U.S. Pat. No. 4,949,187, provide a local disk storage system for storing a digitized multimedia program received from a central archive library. After establishing a telephonic link with the central server 10 over a PSTN telephone network, a selected digitized movie is downloaded in its entirety into the disk storage system incorporated into the terminal unit disclosed in the ""187 patent. This and other home communication systems that employ disk storage systems to provide local storage of a selected multimedia program generally require downloading of the entire multimedia program prior to viewing the program on the subscriber""s television.
Depending on the bandwidth of the telephone line and source transmission rate, the downloading procedure may delay viewing of a selected movie for an appreciable amount of time. Very-high capacity data storage systems are generally required to locally store an entire feature-length movie. Such local data storage systems must generally be configured to allocate several gigabytes of memory for storing a typical movie in a compressed form, and several hundred gigabytes of memory for storing a typical non-compressed movie.
The excessively large memory requirement of these and other conventional local data storage systems employed to store video programming in accordance with a conventional media communication methodology generally results in a commercial product that is prohibitively expensive for the average consumer. Also, such systems cannot provide instantaneous viewing of a selected multimedia program immediately upon receiving the transmission of the program signals from the server 10. Moreover, VCR-type control functionality can only be provided, if at all, after downloading the entire multimedia program onto the disk storage system.
There exists a need in the communications industry for a direct access storage device adapted to store multimedia information received from a media-on-demand communication server system, and a method for efficiently formatting multimedia information on one or more data storage disks disposed in the direct access storage device. There exists a further need for a direct access storage system adapted to provide local VCR-type control over the presentation of a selected multimedia program at a minimal cost to the consumer. The present invention fulfills these and other needs.
The present invention is a multimedia direct access storage device and a method for transferring source program signals representative of a multimedia program to and from the direct access storage device. A multimedia program is transmitted from a multimedia server as a custom ordered series of discrete, digitally compressed program segments and received by the multimedia direct access storage device, which buffers the compressed program segments for subsequent presentation on a local display monitor. The multimedia direct access storage device is preferably incorporated as a component of a local set-top control system for buffering a predetermined number of compressed program segments received from the multimedia server, some of which may be non-sequentially ordered and others of which may be sequentially ordered. A novel formatting methodology provides for the sequential presentation of the program segments asynchronously distributed on one or more data storage disks disposed in the direct access storage device. A user-definable presentation control window for performing local VCR-type presentation control functions for the portion of a multimedia program buffered in the direct access storage device is also provided through the novel formatting methodology. The novel formatting methodology also provides concurrent presentation and buffering of program segments received from the multimedia server for on-demand viewing of a selected multimedia program.